Combination ingot molds and cores and methods of making ingot molds and cores



NOV 30, 1965 F. DETTORE COMBINATION INGOT MOLDS AND CORES AND METHODS OFMAKING INGOT MOLDS AND CORES Filed Jan. '7, 1965 lNvENToR Frank DetorePage.

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United States Patent 3,220,071 COMBINATION INGOT MOLDS AND CORES ANDMETHODS F MAKING INGOT MLDS AND CORES Frank Dettore, McDonald, Pa.,assigner to G. E. Smith, Inc., a corporation of Pennsylvania Filed Jan.7, 1963, Ser. No. 249,829 Claims. (Cl. 22-198) This invention relates tomolds and cores for making ingot mol-ds and to methods of making ingotmolds and particularly to a single stage method of making ingot moldsusing a one-piece pattern.

In the manufacturing of ingot molds it has long been the practice to usemultiple piece patterns or multiple patterns .and a multiple step methodof making the mold and core for the final production of ingot molds.This requires a large expenditure of money for patterns and for patternstorage as well as considerable expenditures in handling and labor madenecessary `by the separate forming of the cores and molds. In addition,the problem of insuring a uniform thickness of the walls of the finalcast ingot mold has plagued this particular segment of the castingindustry. The making of a core and a mold together with a separate stoolraises problems of fin-al assembly which are time consuming and costly.The sand and binder mixture used in the past has required a basic greenstrength at the time of ramming of at least 3 lbs. and usually in thearea of 6 to 8 lbs. Anything less than this would not produce -asatisfactory mold and/ or core, moreover the mold and core have beenwashed with a wash made up of non-refractory highly volatile solids toform a gas shield in the mold. I have discovered a mold and coreassembly and a method of forming molds and cores for the casting ofingot molds which makes possible great savings in labor as well asinsuring uniform quality in the ultimate ingot -mol-d as exemplified byuniform wall thickness in the final mold.

I preferably provide a mold and core assembly which are formed in oneramming operation so that both the mold and the core are formedsimultaneously about a single pattern. In the practice of my invention Iplace a hollow perforate metal arbor centrally of a drag mold. A mixtureof sand and binding agent having a green strength less than 3 lbs. andpreferably zero green strength is rammed into the drag flush with thetop of the drag mold. A one-piece pattern having the contour of theultimately desired ingot mold is centered over the arbor on the rammedsand in the drag. A stripping plate is placed on the sand spaced fromthe outer periphery of the pattern and extending to the edge of the dragmold. An outer flask is placed around the pattern on the stripping plateand attache-d thereto. Sand and binder having a green strength less than3 lbs. and preferably Zero green strength is then rammed about thepattern of the arbor to the level of the inlet gate. This low greenstrength is essential to obtain sand and binder flowability. A tile gateis assembled while the ramming continues until the top of the flask isreached so that the core and mold are simultaneously formed and rammed.The ramming is preferably carried out while imparting shock to the flaskeither by vibration or jolting. The sand is allowed to set upapproximately to 45 minutes. The flask and sand are then removed fromaround the pattern. The pattern is drawn from around the core. The moldand core are then washed with a refractory wash which may be Zircon,silica or carbon or any combination thereof suspended in either Water oralcohol and dried. The mold is returned to its position on the dragflask and is then ready for use.

In the foregoing general description I have set out a generaldescription of the practice of my invention. This invention will bebetter understood by referring to the drawings in which:

FIGURE 1 is a section through a mold flask assembly with a pattern inplace according to my invention;

FIGURE 2 is an isometric View of a one-piece pattern as used in myinvention;

FIGURE 3 is an isometric view of a drag and arbor according to FIGURE 1;and

AFIGURE 4 is a section through a mold flask assembly for a secondembodiment of my invention.

Referring to the drawings, I have illustrated a base plate 10 having anopen center vent 11. A perforated metal .arbor 12 is attached to thebase plate 10 by bolts 13. A drag flask 14 is placed on the base plate10 by conventional rotating pins and clips 15. Cheek flasks carrying astrip plate 17 attached to the bottom thereof are placed on the dragflask containing rammed sand 18. The cheek flasks may be provided withchucks 19 to firmly bond the sand in the cheek flask. A pattern 20 iscentered around the arbor 12. The sand and binder 21 are simultaneouslyrammed into the cheek flask and inside the pattern 20 to form the core.and mold about the pattern 20. The sand-binder mix must be one whichIhas a green strength less than about 3 lbs. and preferably zero or lessthan 1 lb. green strength at the time of ramming and capable of settingup free of deformation without heat. Gate tiles 22 are inserted as thesand ramming continues until the top of the cheek flask is reached.-During the ramming operation the flask assembly is vibrated. A tie -bar23 is attached to the top of the arbor 12 to hold the pattern 2li inplace. As soon as the sand 21 has set, the cheek flask and attached sand21 are pulled away from the pattern 20. The tie bar 23 is removed andthe pattern 20 is pulled from around the arbor and core sand 21. Themold and core are coated with a refractory wash of silica, Zircon orcarbon in water or alcohol. The cheek flask and mold sand 21 arereturned to their original position and the assembly is ready for thepouring of an ingot mold. This practice eliminates the need for separatecore and mold patterns. It eliminates the need for multiple piecepatterns. It makes possible the molding of the core and mold for ingotmold casting in a single ramming operation.

Preferably the sand used to form the core and mold is bonded with abinder requiring no heating such as a cement-dextrose binder or a furanresin binder, thus eliminating the need for placing the mold and core ina furnace to set the same.

In the alternative embodiment shown in FIGURE 4, I provide a base plateand arbor structure identical with that of FIGURE 1. An intermediateflask 40 is placed about the pattern 20a and the core and mold portionadjacent the pattern are rammed with a sand containing a binder capableof setting without the addition of heat at a green strength less than 3lbs. and preferably less than 1 lb. The intermediate flask 40 is thenremoved and the area between the cheek flask and the sand surroundingthe pattern is rammed with sand containing a conventional heat curingbinder at a green strength of about 6 lbs.

By this practice I am able to eliminate a large proportion of expensivebinders which set without the use of external heat and achieveessentially the same result as in the case where all of the sand isbonded by a non-heat requiring binder, the outer layer of sand Ibeingsupported by the intermediate sand layer and the base plate. Thispractice naturally reduces the expense of binders used and adds anadditional factor of savings to the practice of this invention.

While I have illustrated a present practice and embodiment of thisinvention it will be understood that this invention may be otherwiseembodied within the scope of the following claims.

I claim: l

1. The method of forming a mold and core for casting ingot moldscomprising the steps of forming a base of sand and binder in a drag moldaround a central hollow perforate arbor, placing a one-piece patternequidistant around the arbor, placing a iiask assembly around thepattern on the drag mold, simultaneously ramming a sand and bindermixture having a green strength of less than about 3 lbs. about theinside and the outside of the pattern, setting the sand and bindermixture, stripping the outer flask and sand from the pattern whileholding the pattern in position about the arbor, stripping the patternfrom around the sand and arbor within the pattern and returning theflask and sand 4binder to its original position on the drag flask.

2. The method of forming a mold and core for casting ingot moldscomprising the steps of forming a base of sand and binder in a drag moldaround a central hollow perforate arbor, placing a one-piece patternequidistant around the arbor, placing a flask assembly around thepattern on the drag mold, inserting an intermediate flask between theilask and pattern, simultaneously ramming a sand and binder mixturehaving a green strength of less than about 3 lbs. about the inside andthe outside of the pattern Within the intermediate Iask, setting thesand and binder mixture, stripping the intermediate ilask, ramming astandard sand and binder mixture within the remaining area of the outertiask, stripping the outer ilask and sand from the pattern whilehol-ding the pattern in position about the arbor, stripping the patternfrom around the sand and arbor within the pattern and returning theilask and sand and binder to its original position on the drag ilask.

3. The method of forming a mold and core for Casting ingot moldscomprising the steps of forming a base of sand and binder in a drag moldaround a central hollow perforate arbor, placing a one-piece patternequidistant around the arbor, placing a flask assembly around thepattern on the drag mold, simultaneously ramming a sand and furan resinbinder mixture having a green strength of less than flask and sand fromthe pattern while holding the pattern setting the sand and bindermixture, stripping the outer ask and stand from the pattern whileholding the pattern in position about the arbor, stripping the patternfrom around the sand and arbor within the pattern and returning theflask and sand and binder to its original position on the drag flask.

4. The method of forming a mold and core for casting :ingot moldscomprising the steps of forming a base of .sand and binder in a dragmold around a central hollow jperforate arbor, placing a one-piecepattern equidistant .around the arbor, placing a ilask assembly aroundthe patv'tern on the drag mold, simultaneously ramming a stand `:sandand binder in a -drag mold around a central hollow perforate arbor,placing a one-piece pattern equidistant .around the arbor, placing a askassembly around the pattern on the drag mold, gating the mold to entertangentially of the mold cavity whereby erosion of the core is avoided,simultaneously ramming a sand and binder mixture having a green strengthof less than about 3 lbs. about .the inside and the outside of thepattern, setting the sand tand binder mixture, stripping the outer -askand sand from the pattern while holding the pattern in position about Vthe arbor, stripping the pattern from around the san-d and arbor `withinthe pattern and returning the ilask and sand and binder to its originalposition on the drag flask.

References Cited by the Examiner UNITED STATES PATENTS 16,688 2/1857Leonard 22-198 971,045 9/1910 Kerr et al 22-172 1,262,719 4/1918 Walker22-198 1,862,975 6/ 1932 Meloche 22-172 2,770,855 lll/1956 Phillips22-136 I2,860,392 l1/l958 McCracken 22-134 3,008,205 11/1961 Blaies22193 OTHER REFERENCES Dietert: Modern Core Practices and Theories, page417, copyright 1942.

MARCUS U. LYONS, Primary Examiner.

MICHAEL V. BRINDISI, Examiner.

1. THE METHOD OF FORMING A MOLD AND CORE FOR CASTING INGOT MOLDSCOMPRISING THE STEPS OF FORMING A BASE OF SAND AND BINDER IN A DRAG MOLDAROUND A CENTRAL HOLLOW PERFORATE ARBOR, PLACING A ONE-PIECE PATTERNEQUIDISTANT AROUND THE ARBOR, PLACING A FLASH ASSEMBLY AROUND THEPATTERN ON THE DRAG MOLD, SIMULTANEOUSLY RAMMING A SAND AND BINDERMIXTURE HAVING A GREEN STRENGTH OF LESS THAN ABOUT 3 LBS. ABOUT THEINSIDE AND THE OUTSIDE OF THE PATTERN, SETTING THE SAND AND BINDERMIXTURE, STRIPPING THE OUTER FLASK AND SAND FROM THE PATTERN WHILEHOLDING THE PATTERN IN POSITION ABOUT THE ARBOR, STRIPPING THE PATTERNFROM AROUND THE SAND AND ARBOR WITHIN THE PATTERN AND RETURNING THEFLASH AND SAND BINDER TO ITS ORIGINAL POSITION ON THE DRAG FLASK.